Shuffle-furnace bumper



Dec. 13, 1955 Filed Jan. 12, 1955 FIG.I.

P. c. OSTERMAN 2,726,854

. INVENTOR.

ATTORNEY Dec. 13, 1955 P. c. OSTERMAN SHUFFLE-FURNACE BUMPER 2 Sheets-Sheet 2 Filed Jan. 12, 1955 mdE INVENTOR.

ATTORNEY United States Patent SHUFFIE-FURNACE BUMPER Philip C. Osterman, Elizabeth, N. J., assignor to American Gas Furnace Company, Elizabeth, N. 3., a corporation of New Jersey Application January 12, 1955, Serial No. 481,395

6 Claims. (Cl. 263-21) The present invention relates generally to heat treating furnaces and apparatus useful in the treating of relatively small workpieces and is concerned more particularly with improvements in the means for conveying the work stepby-step from a loading station outside the furnace through the heating chamber of the furnace where the treating process is carried out.

A primary aim of the invention is to distribute the work evenly over the furnace hearth and at the same time progressively move the .work in an agitative manner through the heat treating zone so that each piece is subjected to a uniform treatment. A further aim is to feed workpieces received in bulk in a continuously moving stream through the heating chamber and in an eflicient and expeditious manner.

Still another aim of the invention is to effect the feeding of the work along the hearth of the furnace by construct'mg and arranging the hearth that it may be reciprocated to and fro by a simple means that causes the work to skid along the hearth in a forward direction a unit distance each time the hearth movement is abruptly stopped. The work movement here envisaged differentiating basically from other forms of work feeders in that the kinetic energy of moving workpieces carries them forward along the hearth, whereas, in other devices static inertia of the work and a quick shift of the hearth is relied upon to effect progressive advance. With the type of work movement herein provided,- the moving work is caused to slide and in sliding the individual pieces have opportunity to rearrange themselves and turn over from time to time during their progress through the treating zone thus assuring that each receives complete and uniform treatment. Y

in a more restricted aspect the invention aims to provide an improved means and mechanism for agitating the heavy hearth of a furnace so as to effect the foregoing type of work movement and to incorporate therein convenient means for varying the reciprocatory stroke and the number of strokes per unit of time which are factors determining the rate of progress of the work along the hearth and consequently the direction of the treating process that the individual pieces receive.

in carrying out the objectives of this invention it is proposed to equip a conventional furnace having a hearth mounted for reciprocatory movement within the heating chamber with a cam actuated lever mechanism operative to move the hearth forwardly relatively rapidly and rearwardly relatively slowly and to combine with such, mechanism adjustable means for effecting an abrupt stopping of the forward movement at the stroke length desired for the particular class of work being handled. In earlier forms of bumper devices the shock incident to stopping a heavy mass reacted or was reflected somewhat horizontally which meant massive furnace and hearth agitating construction to prevent the structure from pounding itself apart. An aim of this invention is to provide a bumper means wherein and whereby the shock incident to stopping the hearth is transmitted vertically so that the reacting Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection with the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by this invention, drawings depicting a preferred typical construction have been annexed as a part of this disclosure and, in such drawings, like characters of reference denote correspond ing parts throughout all the views, of which:

Figure l of the drawings is an elevational view of this improved hearth reciprocating unit associated with a representative furnace.

Fig. 2 is an enlarged view of the reciprocating means and bumper mechanism shown partly in section.

Fig. 3 is-a sectional view taken substantially along line 33 of Fig. 2.

Referring more particularly to Fig. l, the numeral 10 represents a heat treating furnace that has a heat chamber 11 gas fired as by burners 12. In the furnace shown a tubular muflie 13 is provided for protecting the work, which mufiie receives as reciprocable hearth 14 through its open end 15. The hearth extends within the mufiie and terminates short of the inner end thereof which is downwardly turned to form an exit 16 for the Work. To promote ease of operation the hearth 14 may be supported upon a succession of rollers 17 that are placed between the hearth fioor and the bottom wall of the muffle. The loading end of the hearth, which is trough shaped, projects from the front of the furnace and provides a reasonably sized platform onto which the workpieces may beloaded in the manner appropriate.

The forward end of the hearth is provided with a pair of bearing blocks 19, one at each side, which are adapted to be yoked by a pair of rock levers 20 and 21 that move together and project from the housing of the reciprocating unit 22. The levers 20, 21 are pivotally supported as at 23 in bearings 24 provided by the housing, and at least one of the levers is formed with an extension 25 whose lower end is positioned to be engaged by a rotatable cam 26.

A variable speed drive unit 27 is provided to rotate the cam 26 at the speed desired. The cam 26 is formed with a slowly ascending portion 28 which terminates at its outer end in a substantially radial wall 29. When the cam is revolving counterclockwise in Fig. 2 the lever 20-25 is caused to rock about pivot 23 and slowly retract the hearth 14. When the end of lever 25 rides ofi the high point of the cam, the lever is rocked quickly in the opposite direction and the hearth 14 is advanced. The advancing movement, of the hearth is brought about in this instance by means of a compression spring 30, one end of which abuts a fixed part 31 of the housing and the other end against an adjusting nut 32 threaded on shaft 33. Shaft 33 is pivotally connected with the lever extension 25 as by clevis joint 34. By suitably adjusting the nut 32 the force of the spring 30 may be varied to suit the work load on the hearth.

Stopping of the forward movement of the hearth is,

-in accordance with this invention, brought about by vertically adjustable cradles 37, each of which is mounted to a screw threaded shaft 38. A rotatable nut 39 engages each of the threaded. shafts and is held against axial displacement between fixed flanges 41- and 42 that project from the housing Worms 44 and gears 43 on the bumper block elevating screws are provided to revolve the nuts whereby to raise or lower the bumper block 36 relative to the lever extension 35. Hand wheel 45 connected with the worms 44 is provided for making adjustments. Preferably compression, spring elements 46 clockwise and come to rest suddenly against the underside of the bumper block 36. Any tendency of the block 36 normally supported in spatial relation to the lateral extension in adjustable cradles, and means connected with to lift under the impact is overcome by the weight of the block (in the embodiment disclosed approximately 300 pounds) and the springs 46 pressing thereon. However, whenthe lateral arms 35 strike the block, the integral and projecting levers 20, 21 that are yoked to the trough-shaped hearth 14 are also brought to a quick stop and likewise the hearth. Work pieces that are resting upon the hearth and in motion therewithas the lever 25 falls from the cam are caused to slide forward when the hearth suddenly steps. In this way'the work is-advanced step-by-step along the hearth from its entrance end toward the discharge end.

a From the foregoing it will be seen a furnace hearth reciprocating mechanism is provided in which the forces ,incident to stopping a relatively heavy mass react generally vertically against the mass of the weight 36 and as this weight is ponderous enough to absorb the shock.

without appreciable lifting and the pivot support 23, 24 equally strong a minimum of strain is produced horizontally in the structure and the tie between the furnace proper need be only such as required to maintain registration of the'furnace and bumper units. 7 a

Without further analysis, the foregoing will so fully reveal the gist of this invention that others can, by

applyingcurrent knowledge, readily adapt it for various,

ntilizations by retaining one or morel'of the features that, from the standpoint of the priorart, fairly constitute essential characteristics of either the generic or. specific 'BSPECIS of this invention and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims.

Having thus revealedthis invention, I claim as new and desire'to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the United States:

1 1. In a heat treating furnace having-a heating chamber and a hearth mounted for reciprocatory movement therein the combination of means for reciprocating the in positiontobe engaged by the extension during "movement of the latter in one direction to abruptly stop same.

and define the limit of movement of the hearth in one direction.

2. 'The combination of claim 1 in which the weight is the cradles for adjusting the cradles vertically whereby to vary the reciprocatory stroke of the lever and the hearth connected therewith.

3. A means for imparting re'ciprocatory motion to a member comprising a. lever pivoted intermediate its ends to a relatively fixed support, connections between one end of the lever and the member to be rebiprocated, cam means and splfing means operative on the other end of the lever for impartingoscillatory movement thereto relatively slowly in one direction and relatively rapidly in the opposite direction, said lever also having an arm extending trom its pivot in a direction substan tially normal to the direction of the lever connected with the member to be reciprocated, and a weight mem- I ber freely suspended in the path of movement of the laterally extending arm of the lever so as to be engaged thereby and define the limit of oscillatory movement of the arm in one direction, said weight member having a static force sufficient to overcome the inertia of the moving member so as abruptly to stop the motion thereof.

4. The combination of claim 3 including means for varying the gap normally existing between the extending arm and the weight member when the arm member is in an extreme-position away from the weight whereby to vary the length of stroke imparted to the lever and a V the member connected therewith.

5. In a heat treating furnace having a heat ng chamber and a hearth mounted for reciprocatory movement therein the combination of means for reciprocating the hearth to eiiect step-by-step movement of workpieces therealong comprising a lever member pivoted intermediate'its ends to a relatively fixed support, means operatively connecting one end of the lever to the reciprocable hearth of the furnace, means operative on the other end of said lever for imparting an oscillatory movement thereto through a normally fixed stroke, said lever having an :arm projecting laterally from its pivot, and a relatively massive weight member supported above said arm in offset relation from the pivot of the lever and in position to be struck by the arm, opentop cradle means for supporting said weight member, and means connected with the cradle means for adjusting the cradle means whereby to vary the reciprocatory stroke of the hearth. a

- 6. A means for imparting reciprocatory motion to a reciprocable hearth of a furnace comprising a lever pivoted intermediate into ends to a relatively fixed support, connections between one end of the lever and the hearthto be reciprocated, cam means and spring means operative on the other end of the lever for imparting oscillatory movement thereto relatively slowly in one direction and relatively rapidly in the opposite direction, said lever also having an arm extending from its pivot in a direction substantially normal to the direction'or the lever connectedwith the member to be reciprocated,

and a weight member supported in the path of movement of the laterally extending arm-of the lever so as to be engaged thereby, said Weight member having a static force sufficient to overcome the inertia of the mov 'ing hearth connectedto the lever and to stop the rnovement thereof abruptly, and adjustable means reacting against the weight member for varying the force factor of weight member.

References Cited in the file of this patent unrrnn STATES PATENTS 

